Abstract Name: Dilla Meilani Nst Student No. : 1506102020020 Department/Program : English Education/Undergraduate Title : An analysis Of Word formation In Indonesian Slang Words In Ria Ricis Youtube Vlogs Keywords: Slang words, slang types, slang functions, and word formation. Language as a means of human communication in everyday life involves feelings and emotions that are usually expressed through slang words. This study focused on finding out and describing the types and functions of Indonesian slang words found in Ria Ricis YouTube vlogs. In conducting this research, a descriptive qualitative approach was used. The data source was ten video blogs posted on Ria Ricis’s YouTube account and the instrument was the researcher herself. The data were collected through documentation procedures where the videos were watched repeatedly to observe the slang use phenomena. Then, the data which are identified as slang words were identified were divided into types based on word formation (Yule, 2010) and functions (Zhou and Fangs, 2013) of slangs. From the results, there are two findings. First, concerning the slang type, the most frequent word formation in forming slang words that occurred in ten of Ria Ricis’s Vlogs is borrowing (26 times). It is followed by a clipping (15 times) process. Later, derivation occurred (12 times) and multiple processes happened 11 times. then, coinage occurred for (8 times) and Acronyms occurred for (2 times). Blending was found to be the word-formation with the least occurrences (1 time). Second, related to the use of word functions, the function to express the emotive feelings (11 times), followed by the pursuit of self-identity (6 times) and the least being the function to accomplish politeness in this study was not found.